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RCS *
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RCS questions: 3 problems [[circled]]1[[/circled]] microswitch contamination a μswitch failed on STS-1...general problem with vendor — QC has taken over, & is looking to see where else in vehicle μswitches are located. 

[[circled]]2[[/circled]] steel AC valves (replacing nylon valves) showed some discoloration — may be rust, contractor is analyzing it [[circled]]3[[/circled]] contamination in the OX OMS lines: there was ~40% blockage of the filter between the TK ISOL valves and the ball valves. All the contamination was contained between filters & bellows assemblies. 
[OMS-1 saw: 
P[[subscript]]c[[/subscript]] shift 104 → 123%  
OX INLET P 204 → 193      ⌉   
mixture ratio 1.65 → 1.61] 

[[diagram on left]][[/diagram]]

orange = contaminated area. Nothing got into ball valve assembly, engines or tank isol valves. Had all junk lodged in filter ~96% blockage would have occurred => P[[subscript]]c[[/subscript]]↓ (down to ~80%). Wouldn't have known whether problem was line blockage or tk fail, and would have declared REV 5 entry (mixed XFEED burn). 

contaminent: polyethelene...probably a plastic cap, wrapper, etc.....

Recommending putting in a pressure transducer on other side of filter to measure ΔP across filter could distinguish tank fail from line blockage.

Transcription Notes:
μswitch = microswitch